A DOS emulator for iOS and Mac using DOSBox Staging as the emulation engine. Boots FreeDOS, MS-DOS, or DOSBox's built-in DOS.

qxDOS is a SwiftUI front-end that lets you run DOS on iPad and Mac. The qxDOS project provides only the iOS/Mac app shell — the user interface, touch controls, disk management, and the infrastructure to boot different DOS operating systems. All PC emulation is provided by DOSBox Staging, an independent open-source project. The operating systems themselves — FreeDOS, MS-DOS, etc. — are independent projects with their own developers and licenses. qxDOS did not write or contribute code to any of them.

Choose which DOS to run:

• FreeDOS — free, open-source DOS by the FreeDOS Project (GPL v2+)
• MS-DOS — Microsoft's original DOS; bring your own media, or use MS-DOS 4.0 (MIT license)
• DOSBox DOS — DOSBox Staging's built-in kernel and shell, no OS on disk needed

Use it to run classic DOS games, utilities, learn DOS programming, or explore period software archives like Simtel and Walnut Creek.

• Full 386 CPU with FPU and DPMI support
• VGA/SVGA graphics (S3 Trio64)
• Sound Blaster 16 audio
• Mouse and keyboard input
• Configurable virtual touch controls (D-Pad, analog stick, buttons)
• NE2000 Ethernet networking with SLIRP (FTP, Telnet, HTTP downloads)
• Host file transfer (R and W commands to move files between DOS and your device)
• Disk image management (floppy, HDD, CD-ROM ISO)
• Downloadable disk catalog with FreeDOS images and archive.org collections
• Multiple machine configuration profiles
• Built-in help system with in-app documentation
• iPad and Mac (Catalyst) support

The emulated NE2000 Ethernet adapter connects DOS to the internet through your device's network connection via SLIRP (a virtual NAT router). The FreeDOS disk comes with mTCP, a TCP/IP suite with FTP, Telnet, Ping, and an HTTP downloader.

Type FDNET at the DOS prompt to get online:

C:\> FDNET
Loading NE2000 packet driver...
Getting IP address via DHCP...
Network is ready.

C:\> FTP ftp.example.com
C:\> HTGET http://example.com/GAME.ZIP GAME.ZIP

Two built-in commands let you move files between DOS and your device:

• R (Read) — copies a file from your device into DOS
• W (Write) — copies a file from DOS to your device

C:\> R myfile.txt C:\MYFILE.TXT
C:\> W C:\DOCUMENT.TXT document.txt

Files are stored in the qxDOS folder in the Files app (iPad/iPhone) or the app container's Documents directory (Mac).

The app includes a downloadable catalog of disk images:

• FreeDOS Hard Disk — ~320 MB bootable FreeDOS with 230 utilities, full source under C:\SOURCE\ and per-package SOURCE/ trees
• FreeDOS Starter — ~32 MB minimal bootable FreeDOS, also with kernel/FreeCom/mTCP source
• FreeDOS Boot Floppy (qxDOS) — 1.44 MB FreeDOS boot floppy with attribution/credits
• FreeDOS 1.4 / 1.3 LiveCD — official installer ISOs (from freedos.org)
• MS-DOS 4.0 Hard Disk — 64 MB bootable Multitasking MS-DOS 4.0 BETA from microsoft/MS-DOS, with source ZIP on disk
• MS-DOS 4.0 Boot Floppy — 1.44 MB bootable Multitasking MS-DOS 4.0 BETA
• Simtel MS-DOS Archive — thousands of DOS utilities and shareware (from archive.org)
• Walnut Creek CD-ROMs — classic DOS software collections (from archive.org)

CD-ROM ISOs are downloaded directly from their original hosts. ZIP files are automatically extracted.

In accordance with section 3 of the GNU General Public License, every GPL binary on a bundled FreeDOS disk image is shipped together with its corresponding source code on the same disk:

• The kernel, FreeCom, and mTCP source archives live in C:\SOURCE\
• Each FreeDOS package directory (C:\FREEDOS\<PKG>\) contains a SOURCE\ subdirectory with the package's original source as published by the FreeDOS Project
• License texts (GPL v2, GPL v3, MIT) live in C:\LICENSE\
• Credits and attribution: C:\CREDITS.TXT, C:\README.TXT, C:\SOURCE.TXT

The MS-DOS bundled disk ships with C:\SOURCE\MSDOS40.ZIP (the MIT- licensed production MS-DOS 4.00/4.01 source from github.com/microsoft/MS-DOS) plus C:\LICENSE.TXT.

• Xcode 15+
• XcodeGen (brew install xcodegen)
• CMake (brew install cmake)
• SDL2 and dependencies (brew install sdl2 sdl2_image libpng speexdsp iir1 opusfile)

# Clone with submodules
git clone --recursive https://github.com/avwohl/qxDOS.git
cd qxDOS

# Configure CMake for Mac Catalyst
mkdir build-maccatalyst && cd build-maccatalyst
cmake ../dosbox-ios
cd ..

# Configure CMake for iOS (requires iOS toolchain)
mkdir build-ios && cd build-ios
cmake ../dosbox-ios -DCMAKE_SYSTEM_NAME=iOS
cd ..

# Generate Xcode project
xcodegen

# Open in Xcode and build
open qxDOS.xcodeproj

The Xcode pre-build script automatically runs cmake --build to incrementally rebuild the DOSBox static libraries when sources change.

SwiftUI App (qxDOS/)
  └─ DOSEmulator.h/.mm (Objective-C++ bridge)
       └─ dosbox-ios/ (C bridge layer)
            ├─ dosbox_bridge.cpp — config, lifecycle, input
            ├─ int_e0_hostio.cpp — INT E0h host file transfer
            └─ DOSBox-staging (git submodule)
                 ├─ CPU: 386/486 with FPU, dynamic recompiler
                 ├─ DOS: kernel, DPMI, drives, shell
                 ├─ Hardware: VGA, Sound Blaster, NE2000, keyboard, mouse
                 └─ SDL2: video output, audio, input events

qxDOS is licensed under GPL-3.0-or-later. See LICENSE for the full license text.

This app distributes binaries from several independent open-source projects. Each project's license is respected and its source code is available — both directly on every disk image we ship (under C:\SOURCE\ and per-package SOURCE/ trees) and from the upstream sources listed below:

• qxDOS (GPL v3+) — https://github.com/avwohl/qxDOS
• DOSBox Staging (GPL v2+) — https://github.com/dosbox-staging/dosbox-staging
• emu88 alternate hardware backend (GPL v3+, qxDOS-internal)
• FreeDOS kernel (GPL v2+) — https://github.com/FDOS/kernel
• FreeCom (COMMAND.COM) (GPL v2+) — https://github.com/FDOS/freecom
• FreeDOS utilities (GPL v2+ / BSD) — https://github.com/FDOS
• CWSDPMI (modified GPL v2) — http://sandmann.dotster.com/cwsdpmi/
• mTCP (GPL v3) — https://www.brutman.com/mTCP/
• NE2000 packet driver (Crynwr, GPL v2+) — http://crynwr.com/drivers/
• libslirp (BSD-3-Clause) — https://gitlab.freedesktop.org/slirp/libslirp
• ZIPFoundation (MIT) — https://github.com/weichsel/ZIPFoundation
• MS-DOS (MIT, © IBM and Microsoft) — https://github.com/microsoft/MS-DOS

qxDOS did not write any of the operating systems or emulator cores listed above. All credit for FreeDOS, MS-DOS, DOSBox Staging, mTCP, libslirp, and the rest belongs to their respective authors. qxDOS only repackages their work into a SwiftUI app shell.

You may also request source code by opening an issue at https://github.com/avwohl/qxDOS/issues. This offer is valid for at least three years from the date of each release. See RIGHTS.md for the full attribution list, the trademark notice, and the explicit GPL §3 source-on-disk statement.